Claude 3.5 Sonnet vs o3-mini

Side-by-side benchmark comparison across knowledge, coding, math, and reasoning.

Claude 3.5 Sonnet is clearly ahead on the aggregate, 62 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

o3-mini is the reasoning model in the pair, while Claude 3.5 Sonnet is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.

Quick Verdict

Pick Claude 3.5 Sonnet if you want the stronger benchmark profile. o3-mini only becomes the better choice if knowledge is the priority or you want the stronger reasoning-first profile.

Knowledge

o3-mini

Claude 3.5 Sonnet

55.5

o3-mini

82.1

65
MMLU
86.9
65
GPQA
77.2
63
SuperGPQA
-
61
OpenBookQA
-
74
MMLU-Pro
-
5
HLE
-

Coding

o3-mini

Claude 3.5 Sonnet

44

o3-mini

49.3

57
HumanEval
-
36
SWE-bench Verified
49.3
39
LiveCodeBench
-

Mathematics

o3-mini

Claude 3.5 Sonnet

66

o3-mini

87.3

65
AIME 2023
-
67
AIME 2024
87.3
66
AIME 2025
-
61
HMMT Feb 2023
-
63
HMMT Feb 2024
-
62
HMMT Feb 2025
-
64
BRUMO 2025
-
80
MATH-500
-

Reasoning

Claude 3.5 Sonnet
63
SimpleQA
-
61
MuSR
-
83
BBH
-

Instruction Following

o3-mini

Claude 3.5 Sonnet

83

o3-mini

93.9

83
IFEval
93.9

Multilingual

Claude 3.5 Sonnet
85
MGSM
-

Frequently Asked Questions

Which is better, Claude 3.5 Sonnet or o3-mini?

Claude 3.5 Sonnet is ahead overall, 62 to 56. The biggest single separator in this matchup is MMLU, where the scores are 65 and 86.9.

Which is better for knowledge tasks, Claude 3.5 Sonnet or o3-mini?

o3-mini has the edge for knowledge tasks in this comparison, averaging 82.1 versus 55.5. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Claude 3.5 Sonnet or o3-mini?

o3-mini has the edge for coding in this comparison, averaging 49.3 versus 44. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Claude 3.5 Sonnet or o3-mini?

o3-mini has the edge for math in this comparison, averaging 87.3 versus 66. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for instruction following, Claude 3.5 Sonnet or o3-mini?

o3-mini has the edge for instruction following in this comparison, averaging 93.9 versus 83. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

Weekly LLM Benchmark Digest

Get notified when new models drop, benchmark scores change, or the leaderboard shifts. One email per week.

Free. No spam. Unsubscribe anytime. We only store derived location metadata for consent routing.